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neanderthals
A new study of Neanderthal skulls suggests that they became extinct because they had larger eyes than our species.
As a result, more of their brain was devoted to seeing in the long, dark nights in Europe, at the expense of high-level processing.
This ability enabled our species, Homo Sapiens, to fashion warmer clothes and develop larger social networks, helping us to survive the ice age in Europe.
The study is published in Proceedings of the Royal Society B Journal.
Neanderthals are a closely related species of human that lived in Europe from around 250,000 years ago. They coexisted and interacted briefly with our species until they went extinct about 28,000 years ago, in part due to an ice age.
The research team explored the idea that the ancestor of Neanderthals left Africa and had to adapt to the longer, darker nights and murkier days of Europe. The result was that Neanderthals evolved larger eyes and a much larger visual processing area at the back of their brains.
The humans that stayed in Africa, on the other hand, continued to enjoy bright and beautiful days and so had no need for such an adaption. Instead, these people, our ancestors, evolved their frontal lobes, associated with higher level thinking, before they spread across the globe.
Eiluned Pearce of Oxford University decided to check this theory. She compared the skulls of 32 Homo sapiens and 13 Neanderthal skulls.
She found that Neanderthals had significantly larger eye sockets – on average 6 mm longer from top to bottom.
Although this seems like a small amount, she said that it was enough for Neanderthals to use significantly more of their brain to process visual information.
“Since Neanderthals evolved at higher latitudes, more of the Neanderthal brain would have been dedicated to vision and body control, leaving less brain to deal with other functions like social networking,” said Eiluned Pearce.
A new study of Neanderthal skulls suggests that they became extinct because they had larger eyes than our species
This is a view backed by Prof. Chris Stringer, who was also involved in the research and is an expert in human origins at the Natural History Museum in London.
“We infer that Neanderthals had a smaller cognitive part of the brain and this would have limited them, including their ability to form larger groups. If you live in a larger group, you need a larger brain in order to process all those extra relationships,” he explained.
The Neanderthals more visually focused brain structure might also have affected their ability to innovate and to adapt to the ice age that was thought to have contributed to their demise.
There is archaeological evidence, for example, that the Homo sapiens that coexisted with Neanderthals had needles which they used to make tailored clothing. This would have kept them much warmer than the wraps thought to have been worn by Neanderthals.
Prof. Chris Stringer said that all these factors together might have given our species a crucial advantage that enabled us to survive.
“Even if you had a small percent better ability to react quickly, to rely on your neighbors to help you survive and to pass on information – all these things together gave the edge to Homo sapiens over Neanderthals, and that may have made a difference to survival.”
The finding runs counter to emerging research that Neanderthals were not the stupid brutish creatures portrayed in Hollywood films, but may well have been as intelligent as our species.
Oxford University’s Prof. Robin Dunbar, who supervised the study, said that the team wanted to avoid restoring the stereotypical image of Neanderthals.
“They were very, very smart, but not quite in the same league as Homo sapiens.”
“That difference might have been enough to tip the balance when things were beginning to get tough at the end of the last ice age,” he said.
Up until now, researchers’ knowledge of Neanderthals’ brains has been based on casts of skulls. This has given an indication of brain size and structure, but has not given any real indication of how the Neanderthal brain functioned differently from ours. The latest study is an imaginative approach in trying to address this issue.
Previous research by Eiluned Pearce has shown that modern humans living at higher latitudes evolved bigger vision areas in the brain to cope with lower light levels. There is no suggestion though that their higher cognitive abilities suffered as a consequence.
Studies on primates have shown that eye size is proportional to the amount of brain space devoted to visual processing. So the researchers made the assumption that this would be true of Neanderthals.
Professor George Church, a leading geneticist, is on the hunt for an “adventurous woman” to help turn back the hands of time – and give birth to a Neanderthal baby.
George Church, a genetics professor at Harvard Medical School, believes he can bring back the extinct ancestor of modern man after more than 33,000 years.
Contrary to popular belief, Neanderthals were in fact a highly intelligent race and Prof. George Church believes they could be recreated through modern medicine.
Prof. George Church, 58, told German magazine, Der Spiegel: “I have already managed to attract enough DNA from fossil bones to reconstruct the DNA of the human species largely extinct. Now I need an adventurous female human.
“It depends on a lot of things, but I think it can be done. The reason I would consider it a possibility is that a bunch of technologies are developing faster than ever before.
“In particular, reading and writing DNA is now about a million times faster than seven or eight years ago.
“Another technology that the de-extinction of a Neanderthal would require is human cloning.
“We can clone all kinds of mammals, so it’s very likely that we could clone a human. Why shouldn’t we be able to do so?”
Contrary to popular belief, Neanderthals were in fact a highly intelligent race and Professor George Church believes they could be recreated through modern medicine
Prof. George Church is a pioneer in synthetic biology, which aims is to create synthetic DNA and organisms in the laboratory.
During the 1980s, he helped initiate the Human Genome Project that created a map of the human genome.
George Church admits his project may have shades of Frankenstein about it, but he believes recreating Neanderthals would benefit mankind.
He added: “Neanderthals might think differently than we do. We know that they had a larger cranial size. They could even be more intelligent than us.
“When the time comes to deal with an epidemic or getting off the planet or whatever, it’s conceivable that their way of thinking could be beneficial.
“They could maybe even create a new neo-Neanderthal culture and become a political force. The main goal is to increase diversity. The one thing that is bad for society is low diversity.
‘This is true for culture or evolution, for species and also for whole societies. If you become a monoculture, you are at great risk of perishing.
“Therefore the recreation of Neanderthals would be mainly a question of societal risk avoidance.”
He also explains how the process could theoretically be carried out.
“The first thing you have to do is to sequence the Neanderthal genome, and that has actually been done.
“The next step would be to chop this genome up into, say, 10,000 chunks and then synthesize these. Finally, you would introduce these chunks into a human stem cell.
“If we do that often enough, then we would generate a stem cell line that would get closer and closer to the corresponding sequence of the Neanderthal.
“We developed the semi-automated procedure required to do that in my lab.
“Finally, we assemble all the chunks in a human stem cell, which would enable you to finally create a Neanderthal clone.”
The missing puzzle in his plan is a surrogate mother for the project, who would be a human female.
According to experts, Prof. George Church’s plan is technically possible.
Many of his suggestions formed the central plot-line of the 1993 Steven Spielberg film Jurassic Park, in which dinosaur DNA that had been embedded in chunks of amber was extracted to recreate the monsters that once dominated Earth.
Neanderthals are named after the site in the Neander Valley, Germany, where archaeologists first discovered the species in 1856 – three years before Charles Darwin published his On The Origin Of Species.
A new study suggests that Neanderthals were already on the verge of extinction in Europe by the time modern humans arrived on the scene.
The study used DNA analysis which revealed most Neanderthals in Western Europe died out as early as 50,000 years ago – thousands of years before our own species appeared.
A small group of Neanderthals then recolonized parts of Europe, surviving for 10,000 years before vanishing.
The work is published in the journal Molecular Biology and Evolution.
An international team of researchers studied the variation, or diversity, in mitochondrial DNA extracted from the bones of 13 Neanderthals.
This type of genetic information is passed down on the maternal line; because cells contain multiple copies of the mitochondrial genome, this DNA is easier to extract from ancient remains than the DNA found in the nuclei of cells.
The fossil specimens came from Europe and Asia and span a time period ranging from 100,000 years ago to about 35,000 years ago.
The scientists found that west European fossils with ages older than 48,000 years, along with Neanderthal specimens from Asia, showed considerable genetic variation.
But specimens from western Europe younger than 48,000 years showed much less genetic diversity (a six-fold reduction in variation compared to the older remains and the Asian Neanderthals).
A new study suggests that Neanderthals were already on the verge of extinction in Europe by the time modern humans arrived on the scene
In their scientific paper, the scientists propose that some event – possibly changes in the climate – caused Neanderthal populations in the West to crash around 50,000 years ago. But populations may have survived in warmer southern refuges, allowing the later re-expansion.
Low genetic variation can make a species less resilient to changes in its environment, and place it at increased risk of extinction.
“The fact that Neanderthals in Europe were nearly extinct, but then recovered, and that all this took place long before they came into contact with modern humans, came as a complete surprise,” said lead author Love Dalen, from the Swedish Museum of Natural History in Stockholm.
“This indicates that the Neanderthals may have been more sensitive to the dramatic climate changes that took place in the last Ice Age than was previously thought.”
Neanderthals were close evolutionary cousins of modern humans, and once inhabited Europe, the Middle East and Central Asia. The reasons behind their demise remain the subject of debate.
The appearance of modern humans in Europe around the time of the Neanderthal extinction offers circumstantial evidence that Homo sapiens played a role. But changes in the climate and other factors may have been important contributors.
“The amount of genetic variation in geologically older Neanderthals as well as in Asian Neanderthals was just as great as in modern humans as a species,” said co-author Anders Gotherstrom, from Uppsala University.
“The variation among later European Neanderthals was not even as high as that of modern humans in Iceland.”
The researchers note that the loss of genetic diversity in west European Neanderthals coincided with a climatic episode known as Marine Isotope Stage Three, which was characterized by several brief periods of freezing temperatures.
These cold periods are thought to have been caused by a disturbance of oceanic currents in the North Atlantic, and it is possible that they had a particularly strong impact on the environment in Western Europe, note the researchers.
Over the last few decades, research has shown that Neanderthals were undeserving of their brutish reputation.
Researchers recently announced that paintings of seals found in caves at Nerja, southern Spain, might date to 42,000 years – potentially making them the only known art created by Neanderthals. However, this interpretation remains controversial.
